DE69214744T2 - Zeolite type material - Google Patents

Abstract

The present invention relates to a synthetic zeolite-type material prepared from a reaction mixture containing: 1,3,4,6,7,9-hexahydro-2,2,5,5,8,8-hexamethyl-2H-benzo[1,2-C:3,4-C min -5,6-C sec ]tripyrolium trihydroxide or halide or its precursor or reaction product (hereafter also called the tripyrolium compound); and preferably tetraethylammonium hydroxide or halide or its precursor or reaction product. The zeolite-type material, designated SUZ-9 and suitable for use as an absorbent, catalyst or catalyst base, has, in its dehydrated organic free form, the empirical form m (M2/aO): XzOxz/2 : yYO2, where m is 0.5-1.5, M is an a valent cation; x is 2 or 3 and z is correspondingly 1 or 2; y is at least 2; X is Al, Ga, B, Zn or Fe; and Y is Si or Ge, and in its calcined hydrogen form an X-ray diffraction pattern including significant specified peaks substantially as shown in Table 1: <IMAGE>

Description

The present invention relates to a new synthetic zeolite-type material and a process for its production and use.

US-A-3 950 496 describes the preparation of zeolite ZSM-18 using a synthetic gel which includes as template the material 1,3,4,6,7,9-hexahydro-2,2,5,5,8,8-hexamethyl-2H-benzo[1,2-C: 3,4-C'-5,6-C"]tripyrolium trihydroxide. We have now found that the use of this template, optionally in admixture with another nitrogen-containing template, can produce a new zeolite-type material.

The present invention relates to a material of the zeolite type which, in the dehydrated, organic-free form, has the empirical formula:

m(M2/aO) : XzOxz/2 : YYO&sub2; (I)

wherein m is 0.5 to 1.5; M is a cation of valence a; x is 2 or 3; X is a metal of valence x, selected from aluminum, gallium, boron, zinc and iron; z is 2 when x is 3 and z is 1 when x is 2; y is at least 2; and Y is silicon or germanium; and having an X-ray diffraction pattern of the calcined hydrogen form which substantially includes significant peaks as shown in Table 1.

The material according to the invention is here called SUZ-9.

Preferably X is gallium or especially aluminium. Preferably Y is silicon. The material may contain more than one metal X and/or both silicon and germanium. When X is aluminium and Y is silicon, the material is an aluminosilicate or zeolite. Preferably in formula I m is 0.6 to 1.3 and y is 2 to 15, especially 3 to 9.5, especially 4 to 7.6. Particularly preferred are those zeolite type materials wherein at least one M is an alkali metal having an atomic number of at least 19; for example potassium, rubidium and/or caesium, in particular those wherein M is potassium or a mixture of potassium and sodium and in particular having an atomic ratio of 2:98 to 50:50, for example 5:95 to 20:80.

It is known in the art and should be understood that in addition to the elements represented in general formula I, the material may be hydrated by water in addition to water which is theoretically present when M is hydrogen. The material may also include occluded or adsorbed materials such as nitrogen-containing materials originally present in the synthesis mixture or resulting from the reaction of the originally present materials. The material may also contain more cations M than are required to balance the charge associated with metal X. This phenomenon is described, for example, in J. Chem. Soc. Chem. Commun., 1985, pages 289-290. All such materials should be understood to be within the scope of the invention.

The cation M may, for example, be selected from H+, ammonium, alkali metal cations, alkaline earth metal cations, aluminium cations, gallium cations and mixtures thereof. The cations present in the material as initially prepared will, of course, depend on the materials present in the synthesis gel and may include cations containing organic moieties. An alkali metal, particularly sodium and/or potassium, is usually present, possibly together with cations from organic nitrogen-containing materials. Those cations initially present may, if desired, be replaced in whole or in part by other cations, for example hydrogen ions or metal cations, using conventional ion exchange techniques. The hydrogen form (i.e. M=H+) may be prepared by conventional techniques such as acid exchange or ammonium exchange followed by heat treatment or a combination of the two. For many applications it may be appropriate to produce SUZ-9 in the calcined hydrogen form.

Occluded or adsorbed materials can, if desired, be removed by thermal and/or chemical methods.

The material SUZ-9 can be prepared by co-reacting under aqueous alkaline conditions the following materials: a source of oxide Y0₂; a source of oxide XzOxz/2; a source of M(OH)a; water; 1,3,4,6,7,9-hexahydro-2,2,5,5,8,8-hexamethyl-2H-benzo[1,2- C:3,4-B'-5,6-0"]tripyrolium trihydroxide or halide or its precursor or reaction product (hereinafter also called tripyrolium compound) and preferably tetraethylammonium hydroxide or halide or its precursor or reaction product. The reaction mixture preferably has components in the following molar ratios: YO₂/XzOxz/2 = at least 3, preferably at least 5, more preferably less than 100, in particular 5 to 60, most preferably 5 to 30; H₂O/YO₂ = 5 to 500, preferably 10 to 50 and especially 10 to 30; OH⊃min;/YO₂ less than 1.5, preferably less than 1.0, preferably less than 0.1, in particular 0.1 to 0.8; tetraethylammonium compound plus 1,3,4,6,7,9-hexahydro-2,2,5, 5,8,8-hexamethyl-2H-benzo(1,2-C: 3,4-C'-5,6-0"]tripyrolium trihydroxide compound/YO₂ = 0.01 to 2.0, in particular 0.05 to 1.0. The reaction mixture preferably has a molar ratio of the tripyrolium compound/YO₂=0.01-0.10, in particular 0.03 to 0.10. The reaction mixture preferably also comprises components in at least some of the following molar ratios with respect to XzOxz/2:M2/aO 1-10, for example 1.5-10, in particular 1.5-6.5, K₂O 0.5-8, in particular 0.5-5, Na₂O essentially 0 or 0.5-5, in particular 0.5-2, H₂O 100-700, in particular 200-490 and the tripyrolium compound and tetraethylammonium compound (if present) in total 0.1-5, for example 1-4, tripyrolium compound 0.1-1.0, in particular 0.3-0.9, tetraethylammonium compound (if present) 0.1-10, in particular 1-6. The reaction conditions are selected and maintained such that crystals of SUZ-9 are produced. OH- should be understood as defined below:

a[number of moles of M(OH)a)-(number of moles of M(OH)a, associated with XzOxz/2)].

According to the synthesis, it is possible to adjust the value of y by common chemical methods. For example, y can be increased by treatment with acid, silicon tetrachloride, ammonium hexafluorosilicate, or a combination of vapor deposition and ammonium ion exchange. All of these treatments tend to remove element X from the framework. y can be decreased, for example, by treatment with sodium aluminate or gallate or similar treatments that introduce X into the framework.

The source of oxide YO₂ can be, for example, fumed silica, sodium silicate, silicic acid, in particular silicon dioxide, colloidal silicon dioxide or the germanium equivalent. Fumed silica is preferred.

The source of the oxide XzOxz/2 can be an aluminum salt, aluminum hydroxide, aluminum oxide or a metal aluminate or the equivalent for other metals X. The use of a metal aluminate, especially sodium aluminate, is preferred.

The source of M(OH)a may, for example, be an alkali or alkaline earth metal hydroxide, in particular sodium, potassium, magnesium or calcium hydroxide. A mixture of different materials, for example sodium hydroxide plus potassium hydroxide, may be used. It is particularly preferred that the reaction mixture contains an alkali metal having an atomic number of at least 19, for example as described above for M, in particular potassium or a mixture of potassium and sodium, in particular with an overall atomic ratio for some sources in the reaction mixtures, for example whether added as hydroxide and/or aluminate, of 10:90 to 90:10, such as 90:10 to 40:60.

The process for preparing the material SUZ-9 includes the presence of a template comprising 1,3,4,6,7,9-hexahydro-2,2,5,5,8,8-hexamethyl-2H-benzo[1,2-C:3,4-C'-5,6-0"]tripyrolium trihydroxide or its precursor or reaction product and preferably also tetraethylammonium hydroxide or halide or its precursor or reaction product. The process may involve in situ conversion of the template or templates into the active species during the preparation of SUZ-9 and thus the reaction products of the template or templates may also be used. Similar precursors for the template or templates or the active species may be employed. The molar ratio of tetraethylammonium compound/1,3,4,6,7,9-hexahydro-2,2,5,5,8,8-hexamethyl-2H-benzo[1,2-C:3,4-C'-5,6-C"]tripyrolium trihydroxide compound is preferably in the range of 1:1 to 20:1, especially 1:1 to 10:1.

The reaction mixture is maintained under crystallization conditions until crystals of the desired product SUZ-9 are formed. Generally, a reaction temperature of 80 to 200°C under autogenous pressure is suitable and an optimum reaction time can be determined by monitoring the reaction progress.

As is common in the field of zeolite synthesis, the precise way in which the reaction is carried out influences the final product. Special combinations of parameters can be used to optimize the yield of SUZ-9. Such optimization is a routine part of zeolite synthesis. The new product SUZ-9 can, under certain circumstances, be produced along with other crystalline materials. Special reaction conditions leading to the production of SUZ-9 are given in the examples.

Material SUZ-9 has a variety of potential applications, particularly as a catalyst or adsorbent. As is known in the field of zeolites and zeolite type materials, it can be used in a variety of purifications or separations and a variety of catalytic conversions, for example the conversion of hydrocarbons and oxygenates to other products, including reforming, cracking, hydrocracking, alkylation, etc., with n- and isobutene, hydroisomerization and dewaxing, for example of lubricating oil. Examples of cracking are those of hydrocarbons to other low molecular weight hydrocarbons, such as linear alkanes, for example having 6 to 30 carbon atoms to mixtures of olefins and alkanes and cracking of gas oil and residual oil to lighter oils; temperatures of 300 to 500°C may be used. For example, hydrocarbon conversions include conversions of linear olefin, such as linear C4-6 olefin, for example butene-1, to branched olefin, for example a mixture of branched olefin comprising a major portion of at least 5 carbon atoms; the dimerization and/or oligomerization of olefins and the reaction of at least one olefin, for example having 3 to 20 carbon atoms, with a reactive, usually organic, compound. Examples of such a compound are carbon monoxide, usually mixed with hydrogen to form alcohols, and are also aromatic hydrocarbons. for example those having 6 to 10 carbon atoms, especially benzene or toluene to form alkylated compounds and are also oxygenates, especially methanol, dimethyl ether and/or formaldehyde to form higher olefins. The conversion of methanol to hydrocarbons, especially those having 2 to 4 carbon atoms and/or at least 5 carbon atoms and alkylation of the aromatic hydrocarbons with the oxygenate to form alkylated aromatic reaction products can also be effected via the zeolite type material, just as the reaction of formaldehyde and acetic acid to form acrylic acid can be effected. Examples of suitable conditions for these conversions are passing the feed alone with at least one inert gaseous component, such as nitrogen or another inert gas or an alkane such as butene, over the catalyst at 200 to 600°C, optionally after activation or regeneration with a molecular oxygen-containing gas such as air, or thermal activation in the presence of hydrogen. Pressures of about atmospheric pressure can be used, for example in the conversion of methanol and its reaction with aromatic hydrocarbons and in the production of acrylic acid and in the conversion of linear to branched olefins, although higher pressures, for example 0.2 to 10 mPa absolute, can be used, for example, to convert olefins to alcohols.

In addition to the intrinsic activity of the zeolite-type material, conferred by its porous crystalline structure, it can also be subjected to exchange or impregnation with an element suitable for conferring a specific form of catalytic activity. Metal or non-metal compounds that can be used for ion exchange and/or impregnation can, for example, be compounds of any of the following elements, i.e. those belonging to group IB, IIA, IIB, IIIA, IIIB, IVA, IVB, VB, VIA, VIIA and VIII according to the Periodic Table of Elements according to Mendeleev. Special compounds of copper, silver, zinc, aluminum, gallium, indium, thallium, lead, phosphorus, antimony, bismuth, chromium, molybdenum, tungsten, manganese, rhenium, iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, platinum are preferred.

For use as a catalyst, the zeolite-type material may, if desired, be bound in a suitable binder material. The binder may suitably be conventional alumina, silica, clay or aluminophosphate binders or a combination of binders. The amounts of binder to the total of binder and zeolite-type material may be up to 90%, for example 10 to 90% by weight. If desired, known zeolites may optionally be present with the binder.

Within the specification, reference to an X-ray diffraction pattern naturally represents a powder diffraction pattern obtained on a conventional fixed-slit X-ray diffractometer using copper Kα radiation. Table 1 gives the positions of the significant peaks present in the XRD of fully calcined SUZ-9 in hydrogen form. It should be understood that the full XRD may contain weak peaks in addition to those listed in the table. Where peaks are close together, two or more peaks may also appear as a single peak due to a lack of resolution. It is also understood that the intensities of the peaks can vary widely depending on a variety of factors, particularly the presence of non-framework materials. The presence of water or nitrogen containing materials present in or resulting from the original synthesis gel can alter the relative intensities of the peaks at different d-spacings. Other factors that can affect the details of the XRD include the molar ratios of X to Y and the particle size and morphology of the sample. It is to be understood that the XRD patterns set forth in the examples below are those actually obtained from numerous samples of calcined and uncalcined SUZ-9. Data were collected on a Philips PW 1820 diffractometer using 1/4°, 0.2 mm, 1/4° fixed slits, scanning from 4° to either 32 or 36° 2-θ in 0.025° steps. θ is the Bragg angle; I is the intensity of a peak and Io is the intensity of the strongest peak. Philips APD 1700 processing software was used to determine the d-spacings (in Å units) and relative intensities (100 x I/Io) using copper radiation, copper Kα-1 wavelength = 1.54056 Å.

The following examples illustrate the invention.

The following reagents were used to prepare SUZ-9. Sodium aluminate from BDH 40 wt% Al₂O₃, 30 wt% Na₂O, 30 wt% H₂O (in Examples 2 to 4). Sodium aluminate 61.3 wt% Al₂O₃, 37.8 wt% Na₂O (for Example 5), sodium hydroxide from FSA, distilled water, tetraethylammonium hydroxide from Fluka (40 wt% in water) (for Examples 1 to 4), fumed silica (Cab-O-Sil, M5) from BDH, 1,3,4,6,7,9-hexahydro-2,2,5,5,8,8-hexamethyl-2H-benzo[1,2-C:3,4-C'-5,6-C"]tripyrolium trihydroxide (referred to as TRISQUAT (50 wt% in water) for Examples 2 to 4 and 25.7 wt% in water for Example 5). Potassium hydroxide from FSA

example 1 Production of TRISQUAT

1,3,4,6,7,9-Hexahydro-2,2,5,5,8,8-hexamethyl-2H-benzo[1,2-C:3,4-C'-5,6-C"]tripyrolium trihydroxide was prepared by the method of US-A-3,950,496. It has the structure:

The hexabromomethylbenzene precursor was prepared according to the procedure of A.D.U. Hardy et al., J. Chem. Soc. Perkin II, 1979, 1013.

Example 2

(a) 5.71 g of potassium hydroxide was dissolved in 65.00 g of distilled water and then 14.24 g of fumed silica was added with stirring. 21.81 g of tetraethylammonium hydroxide and 6.70 g of TRISQUAT solution were added to the silica gel with constant stirring. The resulting gel was then added to a solution of 3.00 g of sodium aluminate dissolved in 20.0 g of distilled water and stirred vigorously. The reaction mixture was stirred for a further 1½ hours. The reaction mixture had the following composition:

20.1 SiO2 - Al₂O₃ - 1.2 Na₂O - 4.3 K₂O - 5.0 TEAOH - 0.8 TRISQUAT - 483.9 H₂O

TEAOH = Tetraethylammonium hydroxide

The reaction mixture was placed in a pressure vessel with a volume of 150 cm³ and heated to 135ºC for 116 hours. The pressure vessel was rotated during the reaction. At the end of this period, the pressure vessel was cooled to room temperature and the contents were filtered. The solid product was washed with distilled water and dried at 100ºC. The

Analysis of the product showed the following molar composition

7.4 SiO2 Al₂O₃ K₂O 0.1 Na₂O

By X-ray diffraction analysis, the product was identified as SUZ-9, the X-ray diffraction pattern is shown in Table 2(a).

(b) The material produced from Example 2(a) was calcined in air at 550°C for 16 hours. The X-ray diffraction pattern of the calcined material is shown in Table 2(b).

The sorption capacities of the calcined SUZ-9 for n-hexane, toluene and cyclohexane were 6.8 wt%, 5.3 wt% and 3.1 wt%, respectively (P/Po = 0.6, T = 25ºC).

Example 3

2.86 g of potassium hydroxide were dissolved in 65.00 g of distilled water and then 14.24 g of fumed silica were added with stirring. 21.81 g of tetraethylammonium hydroxide and 9.3 g of TRISQUAT solution were added to the silica gel with stirring. The resulting mixture was added to a solution containing 6.0 g of sodium aluminate dissolved in 20.00 g of distilled water. The reaction mixture was stirred for 1 hour. The reaction mixture had the following molar composition:

10.0 SiO2 - Al₂O₃ - 1.2 Na₂O - 1.1 K₂O - 2.5 TEAOH - 0.6 TRISQUAT - 247 H₂O

The reaction mixture was placed in a pressure vessel with a volume of 150 cm³ and heated to 135ºC for 184 hours. The pressure vessel was rotated during the reaction. At the end of this period, the pressure vessel was cooled to room temperature and the contents were filtered. The solid product was washed with distilled water and dried at 100ºC. Analysis of the product showed the following composition:

5.6 SiO2 - Al₂O₃ - 0.7 K₂O

The product was calcined in air at 550ºC for 16 hours. 6.2 g of the calcined material was refluxed with 120 ml of 1.5M ammonium nitrate solution at 80ºC for 3 hours. The process was repeated twice with intermediate Washing with distilled water was repeated. The zeolite in ammonium form was then calcined in air at 400ºC for 5 hours to produce the hydrogen form. The X-ray diffraction pattern of the calcined SUZ-9 in hydrogen form is shown in Table 4.

Example 4

A reaction mixture was prepared in exactly the same manner as in Example 2 and stirred for 3 1/2 hours. The reaction mixture was placed in a 150 cc pressure vessel and heated at 135°C for 188 hours. At the end of this period, the pressure vessel was cooled to room temperature and the contents filtered. The solid product was washed with distilled water and dried at 100°C. It was then calcined and a portion converted to calcined hydrogen form in a manner described in Example 3 and the X-ray diffraction pattern of the calcined hydrogen form SUZ-9 is shown in Table 3.

Example 5

12.68 g of TRISQUAT solution were mixed with 40.00 g of distilled water and then 9.50 g of fumed silica were added with vigorous stirring. The resulting mixture was added to a solution containing 2.6 g of sodium aluminate and 4.11 g of potassium hydroxide dissolved in 20.2 g of distilled water. The reaction mixture was stirred for 1.5 hours. The reaction mixture had the following molar composition:

10.1 SiO2 - Al₂O₃ - Na₂O - 2.3 K₂O - 0.6 TRISQUAT - 247.9 H₂O

The reaction mixture was placed in a pressure vessel with a volume of 50 cm3 and heated at 135ºC for 93 hours. The pressure vessel was not moved during the reaction. At the end of this period, the pressure vessel was cooled to room temperature and the contents were filtered. The solid product was washed with distilled water and dried at 100ºC. dried. Analysis of the product showed the following composition:

6.6 SiO2 - Al₂O₃ - 0.9 K₂O

The product was calcined as in Example 3 and a portion was converted to the calcined hydrogen form in the manner described in Example 3, but with 0.5 g of solid treated with 50 ml of ammonium nitrate solution and calcining the ammonium form of the zeolite at 550°C in air for 2 hours. The X-ray diffraction pattern of the calcined hydrogen form of SUZ-9 is shown in Table 5.

Example 6

The catalytic activity of the calcined hydrogen form of SUZ-9 of Example 3 was tested in the cracking process of a hydrocarbon. The calcined hydrogen form SUZ-9 was pelletized and crushed to pass 600 µm but not 250 µm sieves. 2.0 g (5.0 mL) of this material was placed in a quartz reactor and activated in flowing air (flow rate 100 mL/min) by raising the temperature of the catalyst at 4ºC/min to 550ºC and then held at that temperature for 16 hours. The catalyst was then allowed to cool to 400ºC before being tested for catalytic conversion of n-dodecane at 400ºC. n-Dodecane was converted at a WHSV of 4.5 in the presence of a nitrogen gas stream (flow rate 79 mL/min, measured at 25°C); WHSV stands for weight of dodecane added per hour/weight of catalyst. After 30 minutes of flow, the conversion of n-dodecane was 13.3% and the molar product carbon selectivities, defined as mole % carbon yield from each molar conversion component/total carbon, were C1-4 alkanes (21.5%), C2-4 alkenes (38.3%) and C5-11 alkane/alkenes (40.2%). Table 1 X-ray diffraction pattern of SUZ-9 calcined hydrogen form Table 1 (continued) Table 2(a) XRD of the product obtained in Example 2(a) Table 2(a) (continued) Table 2(b) XRD of the calcined material obtained in Example 2(b) Table 2(b) (continued) Table 3 XRD of the product obtained in Example 4, calcined hydrogen form Table 3 (continued) Table 4 XRD of the product of Example 3, calcined hydrogen form Table 4 (continued) Table 5 XRD of the product of Example 5 Table 5 (continued)

The X-ray diffraction data in Table 5 show that the product has the structure of SUZ-9 as shown in the XRD of Table 1, since all reflections are at the same location and most of the reflections have the same intensities relative to each other as those in Table 1. Differences in relative intensity in Table 5 may be due to the fact that the crystals of the calcined H-form product of Example 5 are cylindrical and significantly longer than those of Examples 2 to 4. They therefore undergo preferential orientation in the XRD sample holder, causing certain reflections to be more prominent.

Claims (13)

1. Zeolite-type material which, in the dehydrated form free of organic substances, has the empirical formula: m(M2/aO) : XzOxz/2 : YYO&sub2; (I) wherein m is from 0.5 to 1.5; M is a cation of valence a; x is 2 or 3; X is a metal of valence x selected from aluminum, gallium, boron, zinc and iron; z is 2 when x is 3 and z is 1 when x is 2; y is at least 2; and Y is silicon or germanium; and having an X-ray diffraction pattern of the calcined hydrogen form which includes substantially significant peaks as follows: TABLE 1 TABLE 1 (continued) 2. Material according to claim 1, wherein X is aluminum. 3. Material according to claim 1 or claim 2, wherein Y is silicon. 4. Material according to one of claims 1 to 3 in the calcined hydrogen form. 5. Material according to one of claims 1 to 4, wherein M is potassium or a mixture of potassium and sodium. 6. A process for producing a material according to any one of claims 1 to 5, comprising co-reacting a source of the oxide YO₂; water; a source of the oxide XzOxz/2; and a source of M(OH)a; 1,3,4,6,7,9-hexahydro- 2,2,5,5,8,8-hexamethyl-2H-benzo[1,2-C: 3,4-C'-5,6-C"]tripyrolium trihydroxide or its precursor or reaction product under aqueous alkaline conditions; the reaction conditions being selected and maintained to produce a material according to claim 1. 7. The process of claim 6, wherein the reaction mixture comprises at least one alkali metal having an atomic number of at least 19. 8. The process of claim 5 or 6, wherein the reaction mixture comprises potassium or a mixture of potassium and sodium. 9. A process according to any one of claims 5 to 8, wherein the reaction mixture also comprises tetraethylammonium hydroxide or halide or its precursor or reaction product. 10. The process of claim 9, wherein the reaction mixture comprises components in the following molar ratios: YO2/XzOxz/2 = at least 3; H₂O/YO₂ = 5 to 500; OH⁻/YO2 = less than 1.5; tetraethylammonium compound plus 1,3,4,6,7, 9-hexahydro-2,2,5,5,8,8-hexamethyl-2H-benzo[1,2-C:3,4-C'-5,6- C"]tripyrolium trihydroxide compound/YO₂ = 0.01 to 2.0. 11. The process of claim 10, wherein the reaction mixture comprises components in the following molar ratios: YO2/XzOxz/2 = 5 to 30; H2O/YO2 = 10 to 50; OH-/YO2 = 0.1 to 0.8; tetraethylammonium compound plus 1,3,4,6,7,9- hexahydro-2,2,5,5,8,8-hexamethyl-2H-benzo[1C:3,4-C'-5,6- C"]tripyrolium trihydroxide compound/YO2 = 0.05 to 1.0. 12. Process according to one of claims 6 to 11, wherein the molar ratio M2O/XzOxz/2 in the reaction mixture is 1.5 to 10. 13. A process for converting a hydrocarbon or oxygenate to other products comprising passing the feed over a synthetic material according to any one of claims 1 to 5 or produced by a process according to any one of claims 6 to 12.